In application Ser. No. 136,114, filed Mar. 31, 1980, a projection and scanning system is disclosed which can be used to produce a flickerless television signal from motion picture film. As is set forth therein, it is desirable to provide a system which will not only drive the film in a continuous mode, but will also drive the film in a discrete mode so as to enable an individual frame on the motion picture film to be displayed.
As is further set forth in the above-mentioned application, either two motors or one motor may be used to drive the film. In the preferred embodiment taught in the above-mentioned application, two motors are utilized, with one motor driving the film in a continuous mode and the other motor driving the film in a discrete mode so as to enable individual frames of the motion picture film to be scanned.
In order to reduce manufacturing expense, it would be desirable to provide a mechanical film drive which could be used with projection and scanning systems of this type that would allow motion picture film to be driven either continuously or discretely as required, but which would utilize only one drive motor.
As will appear evident from the above-mentioned specification, proper positioning of the motion picture film is an essential task of such a mechanical film drive. Thus, in addition to the requirement that such a film drive utilize only one motor, it would be desirable to provide a mechanical film drive of this type which would enable film registration in a projection gate to be precisely controlled in accordance with vertical synchronization pulses that are used in conventional video signals.